1. Field of the Invention
The present invention relates to a chemical process for the catalytic oxidation of hydrocarbons with molecular oxygen utilizing a cobalt-containing catalyst.
2. Description of the Prior Art
Hydrocarbon oxidation products in large quantities are valuable products for chemically processing polyamides, polyesters or fuel enhancers. Processes for the catalytic oxidation of hydrocarbons with molecular oxygen using a cobalt-containing catalyst are known in the art. DE-A-3 733 782 (Zakladi -0 Azotowe lip.) discloses a process for oxidizing cyclohexane to cyclohexanol and cyclohexanone with molecular oxygen under pressure at a temperature between 150.degree. C. to 200.degree. C. using cobalt naphthenate as a catalyst. JP-A-01 294 646 (Mitsubishi Kasei Corp.) discloses a process for the oxidation of cyclohexane to cyclohexanol and cyclohexanone with molecular oxygen in the presence of, among other things, a magnesium double oxide containing cobalt such as Mg-Al-hydrotalcite, MGO-Al.sub.2 O.sub.3 or a zeolite ion exchanged with Mg.sup.2+ and optionally cobalt ions at a reaction temperature and pressure of from 110.degree. C. to 180.degree. C. and below 100 kg/cm.sup.2 respectively. In a similar oxidation reaction, JP-A-3 303 936 discloses tile use of a certain phyllosilicate catalysts in which cations have been exchanged with cobalt ions.
There are numerous disadvantages associated with the prior art processes. After the oxidation reaction, the cobalt ions must be recovered from the reaction liquid. Cobalt ions introduced into a molecular sieve by cation exchange are present on the surface of the ion exchange material where they are loosely attached, mainly by electrostatic forces. These ions are easily leached out during the oxidation reaction thereby contaminating the reaction product. In addition, the catalytic activity of the molecular sieve is decreased. The actual catalysis may in fact be due to the cobalt ions in solution.
Reaction temperatures in the range of from 150.degree. C. and 200.degree. C. are also considered a disadvantage since they are relatively high and tend to produce reaction products of a darker color. In addition, these reaction temperatures induce chain length degradation in the reaction products.
Because of these disadvantages, there currently exists a need for an economically attractive industrial bulk manufacturing process utilizing cheap hydrocarbon starting materials and operating under attractive, safe, economical and environmental conditions.